SELEUCID ERA, the basis for Jewish reckoning of years during the Second Temple period, and in certain Jewish communities down to the late medieval period and until comparatively modern times. This era, commonly referred to in Hebrew as minyan shetarot (see *Calendar ), coincides with the founding of the Seleucid monarchy, but there are discrepancies regarding the precise beginning of the cycle. Whereas the return of Seleucus I Nicator to Babylon, following the battle of Gaza (autumn 312 B.C.E.), is officially regarded as the date of the founding of the empire, it appears that certain nations, including possibly the Jews, regarded the following year, 311 B.C.E., as the beginning of that era.